Hi,
According to Nitrokey 3 FAQ - Nitrokey Documentation the NK3A Mini should allow up to 100 passkeys and the NK3C up to 35.
However, nitropy fido2 list-credential shows ~61 (5 used, estimated 56 slots left) and ~11 respectively (4 used, estimated 7 slots left).
The keys are currently not used for anything else (there are no GPG / PIV keys or secrets stored).
Firmware version is 1.8.3 on both.
After a factory reset (nitropy nk3 factory-reset) and re-adding it everywhere the NK3C shows 5 slots used, estimated 11 slots left.
This is still less than half the advertised 35 slots 
.
I see the same issue. Updated to 1.8.3 with 11 slots used, 2 spare and my second key shows 10 used 8 available. I tried a factory reset and re-adding credentials and ended up with the same result. As with yours, no gpg or anything else used except passkey.
Either the marketing material is incorrect, or the dynamic allocation has issues. I can understand some level if vagueness but these results seem quite low.
I wouldn’t mind an option to disable all functionality other than passkey if it meant the full memory allocation can be provided to resident credential storage with less guess work on the free slots.
Hopefully once the latest nk passkey firmware ships that will bring the 100 key limit their FAQ suggests then I won’t be as concerned about the 3A NFC which I’ll keep as backups for critical resident passkeys and any non-resident. Still their FAQ really needs adjusting as from forum posts, most seem to be seeing the same issue.
